Insulating packing for electric conductors



April 2, 1935` K, A. JUTHE e-r AL 1,996,646

INSULATING PACKING FOR ELECTRIC CONDUCTORS Filed Dec. 27, 1927 PatentedApr. 2, 1935L PATENT oFFlcE INSULATING PACKING FOR ELECTRIC CONDUCTORSKristian A. Juthe, Newton, 'andAlbert .Ll-Ianson, Arlington, Mass.,assignors to American Electric Furnace Company, a corporation ofMassachusetts Application December 2.7, 1927, Serial No. 242,904

1 Claim.

'I'his invention relates to an insulating packing device for electricconductors, and more particularly for electric conductors passingthrough the walls of a metal container for highly heated and 5 highlycompressed air. There are many processes in the industry which call fora supply of heated air under pressure. By this invention, a container isprovided for compressed air and a heating element is mounted within thecontainer. For example, an electric resistance unit or group of unitsmay be employed, the units being connected to a suitable source ofcurrent through conductors which pass through the wall of the containerand are electrically insulated therefrom. It has heretofore beenconsidered impracticable, if not impossible, to pass a conductor throughthe wall of a pressure tank so as to insulate the conductor from thetank and to preserve the air-tight integrity of the tank, 2oparticularly where the problem was aggravated by relatively hightemperatures in the tank. By this invention, an efficient mountingdevice is supplied which successfully resists high temperatures andpressures while holding a conductor passing through the wall of the tankelectrically insulated therefrom. Further novel and advantageousfeatures of construction and cornbinations of parts will be apparent toone skilled in the art, from the following description of the 30apparatus shown on the drawing, of which,-

Figure 1 is an elevation of apparatus embodying the invention, theexternal wiring connected therewith being diagrammatically shown.

Figure 2 is a plan view of the apparatus. Figure 3 is a sectional detailshowing how the binding posts, which pass through the wall of thecontainer, are insulated therefrom.

Referring to the drawing in detail, a suitable tank or container I isprovided for compressed air which may be supplied through a supply pipeI I which as shown in Figure 1 may open into the bottom of the containerI0. Although the container will operate in any desired position, forconvenience of description it will be hereinafter referred to as in anupright position as illustrated in Figure 1. An outlet port is provided,preferably at the top of the container I0, a suitable pipe I3 beingconnected to the tank at this point. Within the tank I0 we mount one ormore heat- 50 ing elements. In order to supply current to the heatingelements, suitable terminal posts 20 may be provided, each post passingthrough an aperture 2| in the shell of the tank which is preferablylarge enough to permit the post to extend therethrough with clearanceall around it. In

order to insulate the post electrically from the tank and at the sametime to provide an airtight closure for the aperture 2I by means whichwill stand upagainst the pressure of highly compressed air at hightemperatures within the tank I0, the post may be supported by means suchas are illustrated in Figure 3. As shown in this figure, a perforatedplate or annulus 22 may be xed to the wall of the tank I0 around theaperture 2I, the plate 22 having an outwardly extending boss 23 andbeing internally threaded to receive a nipple 24. The nipple 24 ispreferably provided with an interior shoulder 25 against which is fittedthe radial flange 26 of a bushing 21 made of heat-resisting,electrically insulating material, such as porcelain or lava. The bushing21 is preferably constructed to fit closely over the post 20. A secondbushing 28, which may be similar in construction to the bushing 21, isalso fitted on the post 20. This bushing is preferably provided with aradial flange 29 at one end thereof, the flanges 26 and 29 forming endfaces of the bushings which are mutually opposed when the bushings arein place within the nipple 24 and on the post 20 as shown in Figure 3.Between the opposed faces of the bushings, We preferably insert asuitable quantity of insulating packing material 30 which is preferablyheat resisting. Asbestos is suitable for this purpose. A spacing collar3I is mounted on the bushing 28 in such a way as to bear at one endagainst the flange 29. The other end of the collar 3I may be engaged bya cap 32 which as shown is screwthreaded on the outer end of the nipple24. When the foregoing parts are assembled, the cap 32 is set up on thenipple 24, thus pressing against the collar 2I and the flange 29 so asto compress the packing 30 between the opposing faces of the bushings21, 28, the bushing being supported against such pressure by theengagement of its ange 26 with the shoulder 25. Thus the post 20 isstrongly supported and is in actual contact only with the insulatingbushings 21, 28 and the non-conducting packing 3U which also assists informing an air-tight closure for the aperture 2|. In order to provide aremovable external connection for the post 20, the latter may bescrewthreaded as at 33 to receive a pair of nuts 34, between which maybe clamped the end 35 of a suitable conductor. The nuts 34 may beprevented from contact with the cap 32 by the insertion of an insulatingwasher 36 against the outer face of the cap.

It is evident that various modications and changes may be made in thespeciflc embodiment of the invention herein shown and described withoutdeparting from the spirit or scope thereof as defined by the followingclaim.

We c1aim:- l A device `ior packing and insulating an electricalconductorpassingV through an, aperture inV a metal;wal l,- said devicecomprisingga pair, of insulating bushings tted on said conductor havingradial anges at their mutually adjacent A ends and opposing end faces, apacking of insulating material between saidfaoes', ari-interior 1yshouldered nipple adapted to Vreceive said -1 bushings and packingtherein-againstits Shouh KRIsTIAN A. JU'rHE. ALBERT J. HANsoN.

